Physics-
General
Easy
Question
The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity
and 2
and thickness
and 4
, respectively are
and
. The rate of heat transfer through the slab, in a steady state is
, with
equals to

- 1/3
- 2/3
- 1/3
The correct answer is: 1/3
Let the temperature of common interface be
. Rate of heat flow

=
And
=
In steady state, the rate of heat flow should be same in whole system 

= 


(i)
Hence, heat flow from composite slab is

=
(ii)
Accordingly,
(iii)
By comparing Eqs. (ii) and (iii), we get

Related Questions to study
physics-
A solid material is supplied with heat at constant rate and the temperature of the material changes as shown. From the graph, the false conclusion drawn is

A solid material is supplied with heat at constant rate and the temperature of the material changes as shown. From the graph, the false conclusion drawn is

physics-General
physics-
The energy distribution
with the wavelength
for the black body radiation at temperature
is shown in the figure. As the temperature is increased the maxima will

The energy distribution
with the wavelength
for the black body radiation at temperature
is shown in the figure. As the temperature is increased the maxima will

physics-General
physics-
A metal rod of length
has cross sectional areas
and
as shown in figure. The ends are maintained at temperatures
and
. The temperature at middle point
is

A metal rod of length
has cross sectional areas
and
as shown in figure. The ends are maintained at temperatures
and
. The temperature at middle point
is

physics-General
physics-
The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar show in figure, what will be the temperature at the junction of copper ad steel?

The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar show in figure, what will be the temperature at the junction of copper ad steel?

physics-General
Maths-
Which function is shown in graph?

Which function is shown in graph?

Maths-General
Maths-
Which function is shown in graph?

Which function is shown in graph?

Maths-General
Maths-
Which function is shown in graph?

Which function is shown in graph?

Maths-General
physics-
Five rods of same dimensions are arranged as shown in figure. They have thermal conductivities
When points
are maintained at different temperature, no heat would flow through central rod, if

Five rods of same dimensions are arranged as shown in figure. They have thermal conductivities
When points
are maintained at different temperature, no heat would flow through central rod, if

physics-General
physics-
If two metallic plates of equal thicknesses and thermal conductivities
and
are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be

If two metallic plates of equal thicknesses and thermal conductivities
and
are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be

physics-General
physics-
The graph, shown in the adjacent diagram, represents the variation of temperature
of two bodies,
and
having same surface area, with time (
) due to the emission of radiation. Find the correct relation between the emissivity and absorptivity power of the two bodies.

The graph, shown in the adjacent diagram, represents the variation of temperature
of two bodies,
and
having same surface area, with time (
) due to the emission of radiation. Find the correct relation between the emissivity and absorptivity power of the two bodies.

physics-General
maths-
maths-General
maths-
Value of
is
Value of
is
maths-General
Maths-
What is
for two mutually exclusive sets A and B?
What is
for two mutually exclusive sets A and B?
Maths-General
Maths-
Which of the following is set representing neither A nor B?

Which of the following is set representing neither A nor B?

Maths-General
Maths-
Which of the following is set representing B but not A?

Which of the following is set representing B but not A?

Maths-General